WO2013104733A8 - Continuously variable toroidal transmission - Google Patents

Abstract

In a toroidal variator a plurality of rolling elements (20,22) are in driving engagement with an input and output race (10, 14) at respective contact regions. Each rolling element (20, 22) is mounted on a carriage assembly (26) for rotation about a rolling axis, and is being free to pivot about a tilt axis, the tilt axis passing through the rolling element (20, 22) perpendicular to the rolling axis, and intersecting the rolling axis at a roller centre, whereby a change in the tilt axis causes a change in the variator ratio being the ratio of rotational speeds of the races. The tilt axis is arranged at an angle known as castor angle (see Fig.4) to a plane (P) perpendicular to the variator axis (V). Each carriage assembly (26) can cause a movement of the rolling element (20, 22) with a component of rotation about a pitch axis (A, B). The pitch axis is defined as passing through the roller centre and through the contact regions. Pitching the roller elements (20, 22) causes them to tilt, thereby changing the transmission ratio.